Fractional CTO vs Full-Time CTO: Which Do You Need?

Not every startup needs a full-time CTO from day one. Understanding when to hire fractional vs full-time can save you hundreds of thousands of dollars and months of time.

What Is a Fractional CTO?

A fractional CTO provides part-time technical leadership, typically working 10-20 hours per week with your startup. They handle strategic decisions, architecture, hiring, and sometimes hands-on coding — but share their time across multiple companies.

This model has become increasingly popular as startups recognize they need experienced technical leadership without the $300K+ all-in cost of a full-time executive hire.

Side-by-Side Comparison

Factor	Fractional CTO	Full-Time CTO
Time commitment	10-20 hrs/week	40-60+ hrs/week
Monthly cost	$8K-$20K	$25K-$40K+ (fully loaded)
Equity	Usually none or minimal	1-5% (co-founder-like)
Hiring time	1-2 weeks	3-6 months
Flexibility	Can scale up/down easily	Committed relationship
Availability	Scheduled, may not be instant	Always available
Team building	Guides process, helps interview	Fully owns team
Investor perception	May raise questions	Strong signal

When to Hire a Fractional CTO

Pre-seed to Seed stage: You need technical leadership but can't justify full-time cost.
Non-technical founder: You need someone to translate vision into technical strategy.
Technical due diligence: Preparing for fundraise or acquisition and need expert review.
Architecture decisions: Making foundational choices that will affect years of development.
Hiring your first engineers: Need experienced guidance on who to hire and how.
Bridge period: Between technical co-founder leaving and finding full-time replacement.
Specific projects: Scaling infrastructure, security audit, or AI implementation.

When to Hire a Full-Time CTO

Post-Series A: You have budget and need dedicated leadership.
Team of 5+ engineers: Managing a team requires full-time attention.
Complex technical product: Your core differentiator is technology.
Fundraising requirement: Some investors require a technical co-founder.
Rapid scaling: Growing 2-3x per year requires dedicated focus.
Deep domain expertise: Need someone immersed in your specific technology area.

Cost Comparison (12 Months)

Component	Fractional CTO	Full-Time CTO
Base compensation	$120K-$180K	$200K-$300K
Benefits & overhead	$0	$40K-$60K
Equity (opportunity cost)	0-0.5%	2-5%
Recruiting costs	$0-$5K	$40K-$80K
Total Year 1 Cost	$120K-$185K	$280K-$440K

Transitioning from Fractional to Full-Time

Many startups successfully use fractional CTOs as a bridge. Here's how to manage the transition:

Have your fractional CTO help hire their replacement: They know what the role needs.
Plan 1-2 months of overlap: Knowledge transfer is critical.
Document architecture decisions: Create ADRs (Architecture Decision Records).
Maintain relationship: Some fractional CTOs stay as advisors.
Consider conversion: Sometimes your fractional CTO wants to go full-time.